Study details and key findings

For the study, researchers examined 30 tampon products from 14 "top selling" brands sold in the United States, the United Kingdon, and Greece. The researcher assessed each product for 16 different metals, including arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, manganese, mercury, nickel, lead, selenium, strontium, vanadium, and zinc.

Overall, the researchers found "measurable concentrations" of all 16 metals in the tampon products. Toxic metals, like lead, were also detectable in all of the samples tested. Notably, the researchers said that there is no safe exposure level for lead, and people could experience negative health effects if lead were to leach out of a tampon and into the circulatory system.

"Even low-level exposure to [lead] can result in neurobehavioral impacts in adults and children, including decreased cognitive function such as impaired attention, memory, and learning ability," the researchers wrote.

Metals were found in both organic and non-organic tampons, but lead concentrations were higher in nonorganic products, and arsenic concentrations were higher in organic products. According to the researchers, these differences could be due to the types of fertilizer used to grow cotton for organic products.

Tampons from the United States also had higher levels of lead than those from the United Kingdom or European Union.

"Our findings point towards the need for regulations requiring the testing of metals in tampons by manufacturers," the researchers wrote.

Commentary

According to the researchers, further studies are needed to determine whether the metals detected leach out of tampons since the skin of the vagina is more permeable than other parts of the body. This means that any substance the enters the bloodstream from the vagina would not be filtered by the liver.

"We cannot yet say that people should not be using tampons. So far what we know is that metals are present in all the samples we tested," said Jenni Shearston, a postdoctoral scholar at the University of California, Berkeley School of Public Health and the study's lead author. "However, we do not know yet if metals leach out of the tampon and whether they are absorbed by the body. We therefore cannot yet assess to what extent (if any) metals in tampons contribute to any health problems."

"We definitely need more research on this severely understudied area, especially because millions of people could be affected," Shearston added.

Currently, FDA regulates tampons as medical devices, but there is no requirement that tampons be tested for chemical contaminants. The agency only recommends that "tampons not contain two dioxin compounds or pesticides residues," the researchers wrote.

"I really hope that manufacturers are required to test their products for metals, especially for toxic metals," Shearston said. "It would be exciting to see the public call for this, or to ask for better labeling on tampons and other menstrual products."

In a statement to CBS MoneyWatch, FDA said it is reviewing the study's findings, but noted that all studies have limitations.

"While the chemical method used indicates these metals are present in the tampons tested in the laboratory, the study does not assess whether any metals are released from tampons when used in the body. It also does not address whether any metal, if released, can be absorbed into the vaginal lining or, subsequently into the bloodstream," an FDA spokesperson said. "We plan to evaluate the study closely and take any action warranted to safeguard the health of consumers who use these products." (Gibson, CBS News, 7/8; Lotz, Axios, 7/9; Schultz, People, 7/9; Edney, Bloomberg, 7/8; Snelling, Fast Company, 7/8; Shearston et al., Environmental International, accessed 7/10)